#define _CRT_SECURE_NO_WARNINGS 1



#include<stdio.h>

void fun(int* a, int n)
{
	int i, j, k, t;
	for (i = 0; i < n - 1; i += 2)
	{
		k = i;
		for (j = 1; j < n; j += 2) if (a[j] > a[k]) k = j;
		t = a[i]; a[i] = a[k]; a[k] = t;
	}
}
int main()
{
	int aa[10] = { 1,2,3,4,5,6,7 }, a, i = 0;
	fun(aa, 7);
	for (i = 0; i < 7; i++) printf("%d ", aa[i]);

	return 0;
}